I wonder if farther is falling out of use and being replaced by further. Languages change and people use words in different ways so their meaning changes.
With social media you get to see writing from more people and standards of written English seem pretty low. I try to be correct in what I write, but I know I make some mistakes.
BTW This is a cool series on words that get confused https://geekdad.com/tag/word-nerd/
Sometimes when things get too technical it is better to use the right word intended to convey the true meaning. Thanks for the link. It is a good resource. I may even use some of them in my series here in Steemit.